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Biomedical subjects

A L Carter

Publications and source records attributed to A L Carter.

29 records · Page 2Linked to original sources
PubMed1983

Separation of ornithine and lysine activities of the ornithine-transcarbamylase-catalyzed reaction.

Several lines of evidence are presented that an entity is present in mitochondria which converts lysine and carbamylphosphate to homocitrulline, distinct from the ornithine transcarbamylase (OTC): lack of inhibition by lysine of OTC with ornithine as substrate at the pH of the mitochondrial matrix, a Km for lysine of 6.3 mmol/l in the crude mitochondrial extract, versus a Km of 55.3 mmol/l after partial purification of OTC, decrease of the specific activity of OTC with lysine as substrate and increase of the specific activity with ornithine as substrate after heat denaturation, and separation of the activities for ornithine and lysine after isoelectric focusing. This would explain the excretion of homocritrulline in the HHH-syndrome, saccharopinuria, citrullinemia and hyperlysinemia. The fact that homocitrulline excretion is not observed in OTC deficiency suggests that the activity responsible for homocitrulline excretion is closely related to OTC.

Animals↗
PubMed1982

Sex steroid regulation of urinary excretion of carnitine in rats.

The concentration of acid soluble carnitine was determined in several body tissues and fluids in rats under various conditions of sex steroid regulation. Intact female rats had significantly greater liver carnitine concentrations and urinary excretion rates, and lower blood plasma and heart carnitine concentrations than intact male rats. Ovariectomy increased blood plasma carnitine concentrations (P less than 0.01) and the excretion of carnitine in the urine (P less than 0.05). The administration of either estradiol or testosterone to ovariectomized rats did not alter blood plasma concentrations or urinary excretion of carnitine. Orchidectomized rats had similar blood plasma carnitine concentrations when compared to intact males but excreted significantly (P less than 0.01) greater quantities of carnitine in their urine. Administration of testosterone to orchidectomized rats reduced (P less than 0.01), whereas estradiol stimulated (P less than 0.05) the excretion rate of carnitine in the urine; however, blood plasma carnitine concentrations were not affected by these hormones. These data suggest that a major site for modulation of body carnitine concentration in the male resides in the control of kidney excretion by androgens. Liver, heart and skeletal muscle carnitine concentrations were not altered by the administration of either estradiol or testosterone to orchidectomized or ovariectomized rats.

Animals↗
PubMed1982

The anatomy of hope.

Hope is commonly regarded as the feeling that what is desired is also possible. Today, the concensus is that this feeling can increase one's overall ability to cope with stress by reducing fears and anxieties. It is our assumption, therefore, that much of the illness of mankind can be eliminated by enhancing the hope of human individuals.To be able to enhance hope, one must first know what hope actually is and from where it comes by identifying its true determinants. We have, therefore, chosen the task of defining hope and attempting to dissect it into its relevant components so that this important health related property of the human individual may no longer remain in abstraction. This paper reports our approach to this task, the methods used, results obtained, and conclusions drawn.

Attitude to Death↗
PubMed1982

Hope Index Scale: an instrument for the objective assessment of hope.

Although many clinical observations suggest that Hope influences the onset, duration, prognosis, and recovery from mental and physical illnesses, a lack of direct scientific proof persists because no method exists for the objective assessment of hope. We have now constructed the Hope Index Scale, a testing instrument for the measurement of this rather elusive human attribute. Upon testing control and experimental subjects, it was found that score distribution on the Hope Index Scale correlates negatively with Beck's Hopelessness Scale (Pearson r = -.88, P <.001) and is independent of age, race, or sex. It is concluded that this tool can help identify individuals with varying degrees of psychosocial problems and that scores of 150 or below are indicative of pathologic hope deficit often associated with suicide.

Adult↗
PubMed1979

The role of the kidney in the biosynthesis of carnitine in the rat.

Intravenous administration of L-[methyl-3H]-labeled trimethyllysine to rats results in a very rapid accumulation of radioactivity by the kidneys, while the incorporation of the label into the liver occurs at approximately 1% of this rate when calculated per g of wet tissue. The kidneys convert a substantial portion of the trimethyllysine taken up to butyrobetaine and to beta-hydroxytrimethyllysine, a precursor of butyrobetaine, but fail to synthesize carnitine. Significant amounts of radioactivity are recovered in both carnitine and butyrobetaine of hepatic tissue after longer time periods, while the level of labeled trimethyllysine in this organ remains very low. Bilateral nephrectomy results in a marked decrease in the incorporation of label into the liver. These results indicate that in rats, the initial conversion of trimethyllysine to butyrobetaine occurs predominantly in kidney and that the liver capacity for this transformation is considerably smaller than its capacity to synthesize carnitine from butyrobetaine.

Animals↗
PubMed1978

The relationship of choline and carnitine in the choline deficient rat.

Levels of carnitine in choline deficient and choline supplemented rats were measured in heart, skeletal muscle, plasma, and liver after various treatments. A decreased hepatic concentration of carnitine was shown to be closely correlated to the deficiency in dietary choline. No change in the concentration of plasma ketone bodies after a 48 hour fast was observed in the choline deficient rats when compared to choline supplemented controls, even though the level of hepatic carnitine subsequent to the fast was lower in the deficient rats. The concentration of hepatic carnitine was increased to normal values 1.5 hours after a single injection of 100 mumoles of choline, but was not affected by other "methyl" donors. From experiments presented in this communication it is concluded that the increase in hepatic carnitine is probably due to increased transport and uptake of this compound into the liver rather than by "de novo" synthesis.

Animals↗